Blast furnace



BLAST FU'RNACE Filed Jan. 18, 1944 Z'Sheets-Sheet l 9&5 MW,

Mach 19, 1.946. G. A. WHITEHURST Shee'S-Sheet 2 BLAST FURNACE Filed Jan.18, 1944 Patented Mar. 19, 1946 UNITED STAT ES;- PATEN'E VFFICEBLAS'l"FURNGEl l GcorgefAl; Whtehurstt; Mount Lebanon, Pa., as.-`

signor tofCarnegieelllinoisi-Steel' Corporation, 'a

corporation of Ne'vv' Jersey Applicationzlannaryl,1944;;fScraliNm518,765:

7 Clan'sil. (Cl. 26S-32).

A`s presently constructedgblast furnacesA usueally-A are lined?"throughout*l with'. fire-clay:v brick.

The-quality of this brickl is-adjustedtofmeet the particularrequirements of-v different zones of?V the furnaceJ which are` dividedlintofour secti'onsY or parts; namely; the-hearth,V hash, lowen-inwalland upper inwalli The brick of the hearth 'is subjectedltothe=- actionroihighlternperature: and

slag without-being required to stand? any loads or abrasion; Y On thisaccount; its properties-are selected; to showf a1 maximum resistance-'totemperature andi. chemicalaction. Ifn'A Vthe boshi.

section;- the bricl:- isr subjected to-` avery high-1- temperatur-e;attack by the' slag, and -someabrasive action of eolie-passingrL overit, but again it isnot required. to; stand'- any load; Its char--acterist-ics are adjustedl for high chemical' inertness andi`temperature# stability without l any particular attention to'- thevmechanical' properties. the requirements almostequal 'toi those` of thebosli'A section# from -sl'aggingfand `ternperatm'eA stan'dpoints; and atthe s'arne` time must support theweight of# the entireliningon theinside off' the shaft and stand severe abrasion'oausedf-by descendingcharge: YIts properties must; therefore; combine good: resistanceitochemical act-ion and temperature as well vas a'- highmecl'ianical'Vstrength and' abrasion resistanceV at the-tem peratures involved.Properties of brick used for lining the upperinwall aredirected-principally towards exceptionally high-abrasion resistance withbut little attentionbothto'V thechemicalf stability and capability offstanding-high teme peratures.

Advances made inthe manufacture of refrac tories permit to a greatextent the meeting-*of the requirements of three of tl'ieabovementioned-zones namely,v the hearth, bosh and upper inwalllsectiona Thefire brick as now1 producedisi capableof= withstanding both\ tempera-lture and the`d chemical actioninvolved aslv well.

as abrasion in the upper-inwalL- .Thet'emperae ture: in. the lowerpartof thefinwalloi a'. con-` temporaryv blast` furnace variesrusuallybetween 2450 and 2300 F. andavery pronounced soften-4` ing of fire-claybrick occurs ata around 220091?. Consequently; `it will? be seen: that.in order' to support the heavy weight'. of the-superimposed lining; thelower portion. offthe linwafllrrnustbe madee excessivelyfthick. Onlylfew." years ago.

InV thev llower inwall", the brickv must'- meet'.

40,- inches..

IInposs-ibility of obtaining the desired prop. erties; by` use .orbrick' itself; led blast furnace.v technicians vto provide theadditional` required.`

characteristics-.to.thevital parts oi. the furnace by.meanszofzarticially.cooling the lining. Thisx practicebecaniezstandardlas far as the boshand hearthsectionwas concerned andspread: very. widelyit'owardslthe lower .portion Vof the inwall.. In designingablastfurnace, the liningY of boshl sectionsis relieved from any,superimposed..loads,.

solthatithastostand only.` the temperature .and chemicallactioni-offoperating: conditions.. Onthis account',. weakeningfinwall Alining ,byplacing, in. it.v voluniinoi'is cooling devicesas: usedY in the boshsection cannotlbe tolerated; thougfhcooling` prac-- i-,i'ceused` in theconstruction ot the latterade-` quately. meets'` the requirements.Present design` oi'the lower'inwa-ll prevents; however., theapplicationiotwater cooling. or anyother type off coolingltoithe-lowerpor-tionL of the'i'nwall to theextent; oi" assuring the desiredf effect.

'IThef-'inwalll lining; whichrbegins.- at the mantle; plate,A is' at;alli times subjected to` com-pression` exberlt'eol7A by many tons:offrbrick superimposed on it." .This pressure must be absorbed by the resistance of the brickV at` this.level, greatly-sof1 A- substantia-lreductiontened by temperature. of temperature within theY corresponding.areas can-be effected by placinginthe lining. .a suflicient'. number ofcooling boxes ot the type used:` in the=boshlsection, but this practice-l'eadstota pronouncedl weakening ofi the lining. v Coolingboxes,-y.vvlflicli are hollow castings4 .with compara-- tively thinfwalls',have a far lower compression.

streirgtlfiA than brick, and' even at a comparatively low-:temperatureof their operation are not.

in at position to support` the load normally irn-u posedlion brickwork.Limitations placedl there-- byA on the number of'boXeswhichcan beeffec-r tively used per unit of brickwork inthis areaoff the furnace:are too severeto permit a uniform and VreallyD Veicient reduction of theavere-- age-temperature of thelining.

Furthermore, the necessityf'or scattering coo1- i ing boxes throughoutthe mass o'fbrickworkv in; order to balance the weakening produced bytheir use,A eapresseseitselfy in localized cooling, simullocalzation.From. observations: of' blast fui-L naces, the wear on the lining is notuniform but is greatly reduced in the areas where heat absorption bythecooling boxes is rapid enough to keep the temperature below apredetermined level and deeply penetrates the brickwork in the areasbetween the cooling members, at which point the heat removal is greatlyreduced by the insulating effect of the surrounding masonry. Projectionsand indentations in the lining so formed pronouncedly interfere with auniform descentl of the charge, and reduce the lining life to that ofits weakest part. This effect appears to be the most pronounced aroundthe mantle plate, and the lower portion of the inwall, where the effectof high temperature, high heat, and

abrasion is the greatest and presents the least4 dependable part ofblast furnaces, which is, furthermore, the most diicult to repair underoperating conditions.

Heavy lining required at the mantle plate by contemporary furnacedesigns leads also to undesirable conditions in respect to carbondisintegration. Unless refractories used are entirely free from ironinclusions or these inclusions are present in a chemical form preventingtheir easy reduction, there is always a possibility of carbondisintegration of the brick involved. This phenomenon has received muchstudy in the hands of both practical men and scientists and lwas iinallyreduced to a mechanism associated with the reduction of iron oxide tometallic iron oy carbon monoxide. Metallic iron, resulting fromdecomposition, in its turn acts as a catalyst leading to thedecomposition of carbon monoxide to free carbon which precipitatesbetween the individual grains of the brick creating a suicient pressureto completely overcome, or at least greatly decrease, the cohesion amongthem. As these reactions take place at a temperature much lower thanobserved at the inside surface of the lining, a critical zone is createdwithin the body of it where the radiation to the outside balances theheat input from the inside, creating a temperature range leading to thisdecomposition. This zone is usually established at a certain distancebelow the inside surface of the lining and gradually advances towardsthe shell with the wear of the inside layers of the brick. On thisaccount, the wear of the lining up to the point of reaching the originaldecomposition zone is comparatively slow, but, as soon as this brick isconsumed, lining falls very rapidly and out of all proportions to itsnormal Wear.

Necessity of operating the lower inwall under conditions approachingmarginal safety requirements expressed itself in the impossibility ofusing blast furnaces of common design for production of iron alloysrequiring `for their manufacture a somewhat higher temperature range,such as spiegel or ferrosilicon with higher contents of the latterelement. The effect of practice associated with their melting on therefractory lining of the furnace is quite pronounced. While properlywater cooled boshes and hearth are able to withstand it for aconsiderable length of time, the lower inwall lining is so rapidly andseverely affected that switching the burden to the making of thesealloys is permissible only in the latest stages of a furnace campaignwhen the lining is gone far enough to disregard it as an operatingfactor.

These aspects of furnace design are well known to blast furnacetechnicians, and many attempts have been made already to remedy thesituation in some appropriate manner, among whicha particularlyimportant place is occupied by the socalled thin lining. This liningconsisted of only a few layers of bricks applied to a shell, andprotected by an artificial cooling of the shell to produce a temperaturegradient adequate to cause heat elimination at a rate suifcient forpreventing an excessive attack on refractories. Furnaces incorporatingthe above idea have been builtl and run for a considerable time but withrather indefinite success. vThe chiefdiiiculties associated with thistype of lining were principally connected with inadequacy of shellcooling. ,As a general rule, either sprinkling or allowing water to runover the surface of the shell were the vonly means available for heatremoval. Thin-lined furnaces'and other installations incorporating theprinciple of shell cooling from the outside failed; however, inachieving the desired results and led to the return of the presentlyaccepted thick lining.

Furthermore,v any radical changes in thev design of this portion of thefurnace cannot be introduced without pronounced objection, because thelines of the furnaces, after the evolution covering centuries, arestandardized to the extent that'any modification in them beyond changingan angle of inclination by a very few degrees, cannot be tolerated fromthe standpoint of eiciency and the large investment involved. On thisaccount, any modifications which might be introduced have to be adoptedin connection with existing lines of the,v lining, leaving the design oithe shell alone open to further adjustments.

According to the present invention, theV diiiiculties and inconveniencesassociated with the present construction of the lower portion of theinwall are eliminated ina simple and effective manner by raising themantle plate and replacing a portion of the shell lined with therefractories, i. e., the portion extending from the mantle to the jacketof the boshes, with a cooling and reinforcing jacket of a specialconstruction.

Accordingly, it is the general object of the present invention toprovide an improved blast furnace constructed in such a manner that theaforementioned difficulties are eliminated, and at the same time, aconstruction which is strong and rugged and possesses the requiredcharacteristics of a good furnace.v

It is another object of the invention to provide an improved blastfurnace which is simple and inexpensive in its construction, and, at thesame time, efficient and effective in its use.

Y It is a further object of this invention to provide an improved lowerinwall for blast furnaces and the like which may be easily andconveniently incorporated with existing blast furnaces at a minimumamount of expense.

It is still another object of this invention to provide an improvedcooling and reinforcing jacket for the lining of the lower inwall ofblast furnaces and the like. Y

Various other objects and advantages of this invention will be moreapparentin the course of the following specification and will beparticularly pointed out in the appended claims.`

In the accompanying drawings there is shown, for the purpose ofillustration, an embodiment and several modifications thereof which myinvention may assume in practice.

, In thesedrawings:

Figure 1 is a vertical sectional view through the side of a blastfurnace of the conventional type;

Figure 2 is a similar view ,through the side of a blast furnaceconstructed in 'accordance with the assassine-rf present inventionshowing my improved cooling and` reinforcing 1j acket incorporatedltherewith;

Figure13 is a front elevational view of .ai section:` of the improvedcooling and reinforcingfj'acket off:- my invention showing the preferredformtofconf" structiom:

Figure 4 is asectionallview taken onlineIV--IV of Figuref.;

Figure 5 is a sectional;view'taken on line,V-V ofFigureB.;

tionaltype blast furnace as presently used. In

sucha construction, there is provided a hearth sectionL 2. having aboshV section` 3 arranged di'- rectly thereabove withbosh plates larranged in the wallof the furnace'for cooling the same. Di-

rectlyrabove the bosh section 3, there is arranged a. mantle-plate 5which encircles thev furnace and which is supported by columns Epositioned onl the outer side of the furnace in a well known manner. themantle plate 5, there is positioned a relativelyl thickV lower inwallsection 'I having a` series of cooling boxes -arranged in therefractoryv brickwork thereof for cooling the same. 'I-'here is provideda cooling plate 9 which encirclesn the hearth section for cooling thesame. In such a conventional construction, the mantle plate islusuallylocated at a point of'about 25 to 30 feet above thebottomof the hearth.This cor'- respon'dsfto a temperature range within the lower inwallsectionfrom about 2250 to 2450`F. which results' in an'excessivesoftening of the'bricksupporting thev superimposed lining.

According to the' present invention, asshown in Figure`2 of thedrawings, which is a vertical sec tion through the wall of myimprovedblast fur'- nace; a section similar tothat shown in Figure 1,the hearth section 2EL and the bosh section 3a' are substantially thesame as in the conventional type. However, in my construction, themantle plate-5a is positioned at a point above the lower inwall section'lEL and is supported as before, by columns 6a. The refractory lining ofthe lower inwallA section 'la is relatively thin and there is arrangedthere'around and directly next thereto and extending substantiallybetween the mantle plate-5a and the bosh section 3a, an annular coolingand reinforcing jacket l0. This jacket is preferably supported bysuitable means (not shown) carried bythe mantle plate 5a or in anyother' suitable manner. There is arranged aroundi the hearth section 3a,a cooling and re'- inforcing jacket I2 similar 'to the jacket Il) whichwill be described hereafter in detail. In the proposed construction themantle plate is raised and positionedv at a point of about to 40 feet'above5 the bottom of the hearth,A or, in other words; to the level atwhich the-refractory lining is lsubjected to 'a' temperature varyingfrom` about Directly above the bosh section' 3 and l() FigureL Gis across-sectional view'of. a modified-v formiofconstructionof the jacketas: shown. in.

D; to: 2100? F.. and consequently: disposed intthe:

rangezresulting.l in strength andlre'sistancee ampiy.-

capableltovwithstanditheiattack ofoperating. conl-A diti'onsi for.' a'.considerable.- lengthroff time.: By providingisuch:av construction',itZWilLbeLSeeIn that',

the necessity of providing-1a relatively thiclc walls atl the mantle'.plateasA normally" and: aboveV asla. means fori obtaining the. necessarysafety'factorf from? the abrasion resistance standpoint;` is;elimiinated, Vand makeszthe use of cooling.boxesasuperer uous; which',in its turn, .permits .ia i further` thine ning' of; the lining;

It will be seen; that the position of theA mantle'-v f plate in the;proposed. construction: does. notinvolve'. anyIV changes whatsoever inithe inside .lin-. ing. ofthe furnace, for thereason that-the'. con-ytouricfthelining isnotzaffectedj by' the.changeszirrfv outsidedimensions of Athe 'shell oriinf reducing the@` thickness of the'lining' itself.

Asf hereinb'efore' stated, the cooling. and; rein- -1 forcing: jacket Iiextends substantially from' the mantle'plate ila to the bosh'section-3&2, andfis-'in-l tendedl to replace the corresponding portion of theshell 'fwithi its thick' lining of.` refractories; afs:

- shown in r the' conventional' furnace. design; This" jacket isfconstructed inV such a manner as to have sufcient'strength and toprovide a refrac'e' torylining surrounded by it witlisuitabl'ere'efsistan'ce to temperature and chemical. action to whichthis portion ofthe furnace is subjected. The jacket ispreferablyconstructed froml steel or other metals selected to have suicientstrength and formedto coincide with the external' outlines' ofthis-portionl ofthe furnace shell;

In order to increase the protecting power ofthe relatively thinrefractorylining off the lower in wall section la, the jacketIllshould-beconstructedr in such a` manner so asr to assure a uniformabstraction ofheat over the entire areaoff`the2exf--- posed surface so'as to completely eliminate theV deleterious effect of localized coolingas experi'- encedA by theuse of cooling boxes; Accordingly, it isdesirable that the jacket lo b constructed so as-to provide therewithina labyrinthic or`sinuous passageway for conveynig the cooling water orfluid over the entirearea of thejacket.l Such a construction may beprovided in a multitude ofl ways; for example, by sealing, at a certaindis-'f tance from the inner jacket plate;` a sheet of steel? or anyothersuitablematerial having a thickness suiiicient only' to withstand thepressure of water appliedfor cooling purposesand providing, in the spacebetween the jacket plate and this sheet, a series ofv` baffles tocontrol thecirculationof the water or iiuid'in any desired: manner.

By adjusting the rate 0fl water flow through the jacket, it will baseer;that the coolingeffect exerted on the refractories can beregulated tomeet the requirements of melting practice. It will be understood thatwhen" common grades of castiron are made in a blast furnace;acomparativelylow rate of: heat removalY is sufficient to compensate forthe heat produced by the charge: By increasing properly theA heatelimination to take care of hotter charges associated with ferroalloysmelting, itV will be seen that the lower inwall lining of the furnace isprotected from` pre-- mature failure. Accordingly, it will be seen thatafurnace constructedin accordance withthe present invention extends theuse of a blast fur-f ing of certain ferro-alloys occasionallyrequire'aaf cooling rate to be applied to `furnace refractories whichisdiflicult to achieve by means of equipment made of steel. While steelis amply satisfactory from the standpoint of strength, it is well knownthat this metal has a. somewhat low coefficientV of heat conductivity.When a desired rate of heat abstraction from the exposed surface of therefractory lining exceeds the heat absorbing capacity of a coolingjacket, when made of steel, as proposed, the rate of heat abstractionmay be increased by substituting for the steel a metal having a greatercoefficient of heat conductivity, such as copper and some of its alloys.f

YIt will' be understood that by providing a thin lining in'tne lowerinwall section of the blast furnace, in accordance with the teachings ofthe present invention, there results a further advantage of preventingto a great extent carbon disintegration of the brick. It is well knownthat a very considerable dierence between heat conductivities of metaland refractories contracts the zone of temperature at which thisphenomenon takes place to a fraction of that observed in the body of aheavy liningand concentrates it at the outer faces of the brick, i. e.,the face coming in contact withy the cooling plates. Furthermore, thedisintegration zone, once established by the thermal balance, ismaintained in the same position instead of being allowed to traveloutwardly,

as in the case of the conventional thick linings.

Although many types of cooling and reinforcing jackets are suitable forachieving the objects of my invention, I prefer to use a jacketconstructed in a manner as shown in the several embodiments of Figures 3through 1l of the drawings.V The jacket in each of these embodimentsincludes a relatively thick arcuated inner plate I3 which is adapted tobe disposed directly next to the outer side of the refractory lining ofthe inner wall section 72t of the furnace, as shown in Figure- 2. Itwill be understood that the plate I3 reinforces the thin lining of thelower inwall section 1a. The jacket is preferably made in sections withthe abutting edges of the plates I3 welded together as at I3a so as toprovide an annular arrangement which completely encircles the lowerinwall section of the furnace. In the preferred construction, as shownin Figures 3 through of the drawings, there is arranged on the outerside of the arcuated plate I3, a plurality of vertically extendingspaced apart rectangular-shaped members Ill having one of theirlongitudinal edges welded to the plate I3 soV as to provide channelstherebetween. The successive members I4 terminate a short distance fromthe top and bottom of plate I3 so as to provide a continuous sinuouspassageway around and between the members I4. There is securely weldedto the outer longitudinal edges of the members I4 a relatively thinarcuated plate I5 which corresponds in size to the plate I 3 and isspaced therefrom ,by the members I4. There are welded to the ends ofmembers I4 and the plates I3 and I5, top and bottom plates It and Il,respectively, so as to provide an enclosed structure. It will beunderstood, as hereinbefore stated, that the jacket is preferably madein sections primarily for the purpose of handling and ease inassembling, and when assembled in place around the outer shell of theinner wall, the edges are secured together preferably by means cfwelding or in any other suitable manner. There is provided means, suchas cooling'pipes I9 and 20, for conveying the cooling fluid into and outof passageways in each sgction, ,.7 i Y i The construction, as shown inFigure 6 of the drawings, is similar to the preferred construction butdiiers therefrom in that the plate I5 is not one continuous plate. Inthis construction, the passageway formed between each of the verticallyextending members I4 is enclosed by a' rectangular-shaped plate 2i, andthe edges of each of the plates are successively welded to each and toalternating members I4 as at 22.

In Figure 'i' of the drawings, there is shown another modiiication ofthe cooling and reinforcing jacket I0 of my invention. In thisconstruction, there is provided the relatively thick heavy plate I3, asbefore, and on the outer surface thereof there is disposed a pluralityof vertically extending'structu'ral members 23 having substantially aU-shaped cross section. The ends of the leg portions of each of theU-shaped members are welded as at 23St to the outer surface of the plateI3 and to the leg of the next succeeding and abutting U-shaped member soasV to provide a series of U-shaped parallel channels 24 between theU-shaped members 23 and the plate I3. A portionof the material of theleg portions 'of each ofthe members 23, at the top and bottom ofalternate plates, are cut away as at 25, as shown in Figure 8, and thereis arranged between the leg portions and disposed around the cut awayportions formed therein, preferably, a channel-like member 26 forinterconnecting the channels 24 between successive U-shaped members soas to provide a continuous sinuous passageway on the outer surface ofthe plate for conveying the cooling fluid therearound. Between thesections of the jacket there is provided, preferably, a plate memberIllv which is Welded to the outer surfaces of U-shaped members 23positioned at adjacent ends of the sections so as to provide a channel28 between each of the sections.

In Figure 9 of the drawings, .there is shown a slight modification ofthe construction as shown in Figure 7. In this construction, there isprovided a plurality of vertically extending members 29 which arearcuated or substantially open U- shaped'in cross section. They aredisposed on the outer side of the plate I3 in side-by-siderelationshipwith one of the longitudinal edges thereof welded to theouter surface of the plate with the opposed longitudinal edge welded tothe outer side of the next succeeding member 29 so as to provide anirregular-shaped passageway or channel between each of the members 29and the outer side of the plate I3. A portion of the edge of each of theplate members 29 welded to the plate I3 at the `top and bottom ofalternate plates, is cut away as at 30 so as to interconnect thechannels whereby a continuous sinuous passageway is formed along theouter side of the plate I3 for conveying the cooling fluid therealong.As before, there is provided preferably a rectangular plate 3| which iswelded to the outer sides of the adjacent members 29 on the ends of eachof the sections for providingan'enclosed channel at this point.

In the embodiment of my invention, as shown in Figure 1I) of thedrawings, there is provided a plurality of vertically extending anglemembers 32 which are disposed in side-by-side relationship on the outerside of the plate I3. In this modification, the end of one of the legsof each of the members 32 is securely welded to the outer surface of theplate I3 and the edge of the other leg of each of the members is weldedto the outer surface of the next succeeding member 32 so as to providean enclosed channel between two adjacent membersrand the outer side ofthe plate.`

Assiri therconstructionshown in `Figure 9, faipor- :ition rofithe gleg;.which pis-welded fto fthe plate I 3 vis removed, :from :theitop .and.bottom .of :alternate plates, sons atozinterconnect the channels formedbvthe members 32 whereby 1a continuous lsinuous passageway-pis fprovidedalong .the outer vside of 'tliezplate J3. f

i'nliigure lll of the rdrawings, there is shown stillanother modifiedAferm o f J construction :of fthe :jacket Irl-this constinction, thereis provided a .plurality ofvertically extending T-gshapedstruc-:turalzmembers :33 .whichare disposed in .side-by- :side-relationship i.on thev outerside of the plate ,13. .Thezbottom .edge of the upright orverticalportion offeach Aof v'the T-,shaped members :is :welded to theouter surface of the plate i3, andithe r.ad-

1 jacentedgesiof Y,the cross portions;of3the"l'fshaped members tarewelded V,to vvthe 'abutting fedgesfof the :cross-*portions'oftad-jacentT-shapedimemhersfpo- `sitioned tto .either .side thereof iso `:as totprovide :an enclosed :channel vbetween ltwo :succeeding T-.shapedmemberszand the outerside nf the-plate d3. Likewise, Ain thisconstruction, ,'a'iportion of the :upright .portion of the Tlf-shaped:members 333,. at the itop and bottom .of 'alternatefmem'bera js cutaway;orzremoved, so :as ito interconnect the channels, thus againyproviding a continuous 'pas- :sagewaypn the `outer-side of the plate..'Itwill be zunderstood that in all thesemodied construcvtions,.there isprovided top v'and bottom fplates, ,lsirnilar to `.plates It and llinthepreferred vconstruction for enclosing the :respectivezzstructures.

the vertical arrangement is the most satisfactory, and practical,because of the ease in fabrication and assembling thereof While thecooling and reinforcing jacket heretofore described is particularlyadapted for creating conditions of an adequate heat absorption in thelower inwall portion of the furnace, it will be understood that such ajacket can be used to advantage in any part of the furnace where aneicient and uniform cooling is required, as for example, around thehearth. In fact it is desirable that the cooling and reinforcing jacketof the construction above described be used as the cooling jacket l2 forthe hearth, as shown in Figure 2 of the drawings.

While I have shown and described several specic embodiments of myinvention, it will be understood that these embodiments are merely forthe purpose of illustration and description and that various other formsmay be devised within the scope of my invention, as dened in theappended claims.

I claim:

1. A jacket for cooling and reinforcing the lower inwall section ofblast furnaces and the like comprising a plurality of arcuate-shapedsections continuously arranged around the furnace wall having theiredges welded to each other so as to provide an annular arrangement, eachof said sections consisting of an arcuate-shaped relatively thickmetallic inner plate which is -adapted to'rbe vdisposed ldirectly nextto the-furnace wall, a plurality -of members arranged on the outersurface of said plate sonas ltoprovide `anon-tinuoussinuousfpassageway-along the outer .surface rof :said plate, and meansfor introducing `Aa .cooling fluid into said passageway for coolingsaidplate.

:A 'jacket for cooling and reinforcing vthe l ;.lower.inwall section ofblast furnaces and the like .comprisingapluralityfof sectionscontinuously arranged ;,around vthe furnace wall having theiredgeswelded vto each `other so as to provide an annulargarrangementeachof said sections consistinglof an arcuatefshaped relatively thick inner`plate whichxis adapted =to be disposed directly next to the ffurnacewall, a plurality of substan- `tially parallel members disposedvertically on the ".outergsurface,ofsaid Jplate fand securely weldedxrectly -neXt uto `the .furnace wall, a lplurality of spaced apartparallel,rectangulareshaped r`metal- `licmembers,disposed vertically onthe outer surface of said plate having their edges welded to the outersurface thereof so as to provide a channel successively between each ofthem with successive members terminating short of the extreme bottom andtop of said plate so as to provide a continuous sinuous passageway alongthe outer surface of said plate, an arcuate-shaped outer platesubstantially conforming in size to said first mentioned plate welded tothe outer edges of said rectangular members so as to be spaced from saidfirst mentioned plate and to enclose the channels between said parallelmembers, top and bottom plates welded to both of said innerand outerplates so as to provide an enclosed structure, and

means for introducing a cooling fluid into said continuous passagewayfor cooling said first mentioned plate.

4.'A jacket for cooling and reinforcing the lower inwall section ofblast furnaces and the like comprising a plurality of arcuate-shapedsections continuously arranged around the furnace wall having theiredges welded to each other so as to provide an annular arrangement, eachof said sections consisting of an arcuate-shaped relatively thickmetallic inner plate which is adapted to be disposed directly next tothe furnace wall, a plurality of parallel U-shaped channel-like membersdisposed vertically on the outer surface of said plate with the ends ofthe leg portions of each of said U-shaped members abutting each otherand securely welded to said plate and to each other successivelytherearound so as to provide `an enclosed channel between each of saidU-shaped members and said plate, and means structure, andmeansrforintroducing a cooling fluid into said passageway for coolingsaid first mentioned plate.

5. A jacket for cooling and reinforcing the lower inwall section ofblast furnaces and the like comprising a plurality of arcuate-shapedsections continuously arranged around the furnace wall having theiredges `welded to each other so as to provide an annular arrangement,each of said sections consisting of an arcuate-shaped relatively thickmetallic inner plate which is adapted to'be disposed directly next tothe furnace wall, a plurality of parallel channel-like members having anarcuate-shaped cross section disposed vertically on the outer surface ofsaid plate, one of. the longitudinal edges of each of said memberssecurely Welded to the outer surface of said plate with the opposedlongitudinal edgefof each of them securely welded to the outer side ofthe next successive member around the plate so asl to provide anenclosed channel between each of said members and said plate, each ofsaid channel-like members having a portion removed therefrom alternatelyat the top and bottom of successive members at a point adjacent the edgeWelded to the plate so as to interconnect the channels formed therebywhereby a continuous sinuous passageway is provided along the outersurface of said plate, top and bottom plates welded to` the ends of saidchannel-like members and said plate so as to provide an enclosedstructure, and means for introducing a cooling uid into said passagewayfor cooling said plate.

6. A furnace of the class described including a hearth having a boshsection arranged thereabove, a relatively thin lower inwall section madeof a refractory material arranged above said bosh section, a mantlearranged around said furnace at a point immediately above said lowerinwall section, and a cooling and reinforcing jacket consisting of arelatively thick metallic plate arranged peripherally around anddirectly next to the thin refractory lower inwall section of saidfurnace so as to comptely encircle the same and extending substantiallybetween said mantle and said bosh section, and means arranged on theouter side of said plate forming sinuous passageways for continuouslyconveying a cooling fluid around the outer surface thereof for coolingthe same.

7. A furnace of the class described including a hearth having a boshsection arranged thereabove, a relatively thin lower inwall section madeof a refractory material arranged above said bosh section, a mantlearranged around said furnace at a point immediately above said lowelinwall section, and a cooling and reinforcing jacket consisting ofrelatively thick metallic plates integrally joined together arrangedperipherally around and directly next to the thin refractory lowerinwall section of said furnace so as to completely encircle the same andextending substantially between said mantle and said bosh section, andmeans arranged on the outer side of said plates forming sinuouspassageways for continuously conveying a cooling duid around the outersurface Ythereof for cooling the same.

GEORGE A. WHI'IEHURST.

